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With no brains, no heart, and no blood, it’s amazing jellyfish have existed for 650 million years!
These magical floating marine creatures, which consist of 90% water, have fascinated people for centuries! Jellyfish are not actually fish, and are scientifically known as Cnidarians. What is truly remarkable about these animals is that they are have no structured organ systems, heart, brain, or breathing apparatus! Yet they move like silent mysterious ghosts in oceans all over the world and survive by stinging and killing prey with their lethal tentacles and digesting them in their stomach cavity that is enclosed in a gelatinous covering called a mesoglea.
For as much as human beings don’t understand too much about them, they don’t mind eating them. Jellyfish are a delicacy in many parts of the world and are even sometimes eaten raw. They are also harvested, dried and are a good source of mineral collagen which is used in medicines to cure the symptoms of arthritis.
Did you know? One particular species of jellyfish, turritopsis nutricula, is the only living species that is immortal! Scientists have discovered that adult jellyfish can reverse their lifecycles from a medusoid adult to a polyp (larval immobile stage), and then start to grow back into adults again. So they never really die!